Fluid pressure operated head for setting mandrel rivets

ABSTRACT

A fluid pressure operated tool, is disclosed for setting blind rivets by pulling and breaking their mandrels. In addition to including means for ejecting the spent mandrel portion, the rivet head has mechanism for ensuring that its mandrel gripping jaw close prior to exerting substantial mandrel tension, open at the end of the mandrel pulling stroke, and allow reloading of the head with retention of the next mandrel rivet to be installed.

United States Patent 1111 3,630,067

[72] In en or Jam Hens a 3,088,618 5/1963 Pickford 72/453 X SuttonColdfield, England 3,254,522 6/1966 Elliott et al, 72/391 [21] Appl. No.33,273 3,451,248 6/1969 Bell 72/391 [22] Filed Apr. 30, 1970 3,548,62712/1970 Henshaw 72/409 X [45] Patented Dec. 38, 1971 FOREIGN PATENTS[73] Ass'gnee 665,207 1 1952 Great Britain .1 72/391 Priority y 3690,174 4/1953 Great Britain 72/391 Great Britain 384,333 2/1965swltzerland 72/391 [31] 23,895/69 Primary Examiner- Robert D. BaldwinAssistam Examiner-John E. Roethel Attorneys-Richard A. Wise, Richard B.Magley and Carl E.

[54] FLUID PRESSURE OPERATED HEAD FOR J h SETTING MANDREL RIVETS 4Claims, 4 Drawing Figs.

ABSTRACT: A fluid pressure operated tool, is disclosed for [52] US. Cl7222/;7/951l, semng blind rivets by pulling and breaking their mandrelsIn into IIIIIIIIIIIIIIIIII n 821! 9/05 addition to including means forejectmg the spent mandrel B21d3l/06 portion, the rivet head hasmechanism for ensuring that us mandrel gripping jaw close prior toexerting substantial man- [50] held of Search 23 32? drel tension, openat the end of the mandrel pulling stroke.

and allow reloading of the head with retention of the next mandrel rivetto be installed.

[56] References Cited UNITED STATES PATENTS 2,088,859 8/1937 Huck 72/391X PATENTEOuEc28|sm 3,630,067

SHEET 1 [1F 2 lnvenlor James N/lenshazu By hi5 Attorney PATENIEB DEC28um SHEEI 2 OF 2 FLUID PRESSURE OPERATED HEAD FOR SETTING MANDREL RIVETSCROSS-REFERENCE TO RELATED APPLICATION A copending application Ser. No.824,946, filed May 15, I969 in the name of James N. Henshaw discloses afastener inserting machine of the type in which a rivet head such as isdisclosed herein has particular advantage.

BACKGROUND OF THE INVENTION Pull-to-set blind rivets commonly include atubular rivet having a mandrel extending axially therein, the mandrelhaving an upsetting head larger than the rivet bore and a stem portionwhich is tensioned axially as the rivet is held against displacement tocause the blind end of the rivet to be upset.

Fluid pressure operated blind riveting tools have heretofore beenprovided wherein mandrel gripping jaws have tensioned and broken themandrels, an example being the disclosure of U.S. Pat. No. 3,254,522,filed Jan. 29, 1964 in the name of R. M. Elliott. In order to provide afully effective operating stroke in a tool of this type, however, it ishighly desirable that the gripping jaws be prevented from sliding on amandrel before it is tensioned, and that an expulsion of each broken offmandrel portion or other phase of an operating cycle not interfere withor retard reloading of the tool in its succeeding cycle. The presentinvention, while acknowledged to be of use broadly in wire tensioningmechanism, is particularly advantageous in a high production lineemploying a riveting machine of the sort disclosed in the above citedI-Ienshaw application.

SUMMARY OF THE INVENTION In view of the foregoing it is an object ofthis invention to provide an improved head for a riveter adapted to setmandrel rivets, the head to comprise mandrel gripping jaws, and fluidpressure mechanism for controlling the jaws whereby they effectivelyclose at the beginning of a setting stroke and are automatically openedat the end of the stroke to permit rearward ejection of the spentmandrel portion.

A further object of this invention is to provide a riveting tool ofsimple, reliable construction employing fluid pressure mechanism forcontrolling the relative radial positions of the mandrel pulling jaws atthe beginning and end of their operating stroke whereby successivemandrel rivets are cyclically loaded and installed in a rapid manner.

To these ends, and in accordance with a feature of the invention, a jawcase is axially movable in a riveting body and coupled to an innersleeve operable by fluid pressure, air pressure constantly urging thesleeve in one direction and hydraulic pressure being applicable inopposing direction to cause the jaws in the case to pull and break themandrel of a mandrel rivet, the arrangement being such that the jaws,initially open to receive the mandrel, are closed for gripping it beforetensioning is exerted and opened at the end of the mandrel pullingstroke to permit mandrel ejection and reloading.

BRIEF DESCRIPTION OF THE DRAWING The foregoing and other features of theinvention will now be more particularly described in connection with anillustrative embodiment and with reference to the accompanying drawingsthereof, in which:

FIG. 1 is a view in side elevation of an automatically fed rivetingmachine, largely corresponding to that disclosed in the cited Henshawapplication, in which the riveting head of this invention may bemounted;

FIG. 2 is an enlarged view, largely in axial section, of the rivetinghead in rest position, its jaws being shown open and positionedforwardly;

FIG. 3 is a section taken on the line IIIIII of FIG. 2; and

FIG. 4 is a detail view illustrating the releasable operating connectionof a pulling jaw shown in FIGS. 2 and 3, as seen when viewedtransversely of the head.

DESCRIPTION OF THE PREFERRED EMBODIMENTS It will be understood fromreference to the Henshaw appli cation referred to above and withreference to FIG. I herein that automatic transfer mechanism generallydesignated I0 may be employed to present successive mandrel rivets froma raceway 12 into a position wherein a riveting head 14 may be advancedaxially to receive their mandrels individually for setting of the rivetswhen inserted in a workpiece hole. It will, of course, be appreciatedthat, when desired, each mandrel rivet may also be initially thrustmanually axially into the mandrel head 14 for upsetting as willhereinafter be described. In either case a nosepiece 16 (FIGS. 1, 2) ofthe tool will abut a preformed flange of the rivet (not shown) to be setwhen the mandrel is actually retracted.

The head 14 is reciprocable along a guideway 17 (FIG. 1) by means of adouble-acting cylinder 18, the arrangement in the illustrative machinebeing such that in its lowermost position a stem portion of the mandrelof the mandrel rivet to be upset will extend through an end opening 20of the nosepiece 16, between three cooperative pulling jaws 22 (FIGS. 2and 3) mounted as will shortly be explained, and into the front end of amandrel expulsion tube 24 axially extending rearwardly through the head.In addition to the nosepiece 16, the head 14 is coaxially comprised of apartly conical cap 26 threadedly receiving the nosepiece, and asquare-sectioned, hollow block portion 28 threadedly secured to the cap26.

The jaws 22 are respectively slidable axially in inclined equispacedbores 30 formed in a jaw case 32. The axes of the cylindrical bores 30preferably extend about 12 to the longitudinal axis of the head 14,which axis is coincident with that of the opening 20 and a central bore34 (FIG. 2) of the jaw case 32. Mandrel gripping surfaces 36 of the jaws22 may be convex and transversely serrated as indicated in FIG. 3.Radially outer or rearward ends of the jaws 22 are T-shaped as shown inFIG. 4 and releasably connected, as by mortise and tenon arrangement, tothe forward end of a tubular jaw-controlling member 38 axially shiftableby power mechanism later described.

For causing the jaws 22, when closed on a mandrel stem, to tension andbreak it, the stem often having a neck portion for this purpose, the jawcase 32 is threadedly secured in the front end of a tubular pullingsleeve 40 (FIG. 2) slidably disposed within the member 38 and movableaxially with the tube 24. The rear end of the pulling sleeve 40 slidablyextends through a sealing ring 42 seated in an end cap 44 threaded intothe back end of the block 28. The latter is also, for reasons laterexplained, formed to threadedly receive a coupling 46 of a hose 48connected to a source of air under pressure. The rear portion of theexpulsion tube 24 extends into the mouth of a venturi tube 50 (FIG. 2)and is received in an adapter 52 one end of which is threaded into therear end of the sleeve 40.

In order to control axial movements of the tubular member 38 and thesleeve 40 relative to the head 14 the block 28 is in effect divided intoa rear cylinder 54 and a front cylinder 56 by means of a composite seal58 one face of which abuts an annular shoulder 60 formed in the block28. A piston 62 in the cylinder 54 is mounted, preferably with a smalldegree of freedom for compensating movement, on the sleeve 40 and isheld against a flange 64 formed thereon by means of a seal 66 and aretainer ring 68 seated in an annular groove formed on the sleeve 40.The axial position of the ring 68 determines the extent to which thejaws 22 can be separated radially for accommodating different mandreldiameters and ensures that hydraulic pressure is operable on a rear face69 of the member 38 for a purpose later mentioned.

On the opposite side of the piston 62 from the air coupling 46 an inlet70 admits hydraulic fluid under pressure via a hose 72 (FIG. 1)connected to a pneumatic intensifier (not shown herein but identified byreference character 168 in the abovecited I-Ienshaw application). Thearrangement is such that when a spring-retum valve 73 (FIG. I) in an airexhaust line 75 (designated 174 in the prior Henshaw application)associated with the intensifier is actuated by the downward movement ofa setscrew 77 carried by the head 14, which is descending to receive themandrel to be pulled, hydraulic pressure is thereby admitted into theleft-hand chamber of the cylinder 54, as viewed in H6. 2, to force thepulling sleeve 40 rearwardly against the air pressure in the right-handchamber of the cylinder 54.

Affixed on the jaw control member 38 in the front cylinder 56 by meansof a pair of retaining springs 74, 74 is a piston 76 having slidingengagement with a cylindrical lining 78. The latter has its rear endabutting the seal 58 and its front end disposed against the rear face ofa composite seal 80, the front face of which contacts the rear end ofthe cap 26. The lining 78 serves to substantially equate the diametersof the cylinders 54, 56. On the rear side of the piston 76 there is anair exhaust port 82 provided for the cylinder 56, and in front of thepiston 76 is an air inlet 84 connected by a hose to the aforementionedexhaust line 75 of the intensifier. Accordingly, when the valve 73 ofthat exhaust line is closed air under pressure is admitted to thecylinder 56 in front of the piston 76 to open the jaws 22, and when thevalve 73 is open the front of the cylinder 56 is opened to exhaustthrough the inlet 84.

When the jaws 22 break off and release the rearward or spent mandrelportion at the end of a riveting cycle, the mandrel is caused by asmall, continuous stream of air admitted to an inlet 86 (FIG. 2) in theadapter 52 to be carried rearwardly through the tube 24 and a connectingair and mandrel exhaust hose 88. This airflow also assists the head 14,during its advance for receiving the next mandrel rivet presentedthereto, to hold the mandrel in a fully retained condition between theopen jaws.

Operation of the head 14 will now be reviewed as employed in theillustrative machine, it being understood that in the event the headwere embodied in a hand-held tool coupled to fluid pressure lines, amanually operable trigger would be used to actuate the valve 73. in therest or head retracted position shown in FIG. 1 the valve 73 is closedand air pressure behind the piston 62 is holding the inner or pullingsleeve 40 and the jaw case 32 forwardly with the jaws open and the caseabutting an inner face of the nosepiece 16. When the head 14 is advancedto enable the jaws 22 and the tube 24 to receive an end of the mandrelrivet inserted in a workpiece, the valve 73 is opened automatically bythe screw 77, thereby causing the intensifier to introduce hydraulicfluid into the inlet 70, air being released to atmosphere from thecylinder 56. The hydraulic pressure is effective in front of the piston62 by action on the rear end face 69 of the jaw-controlling member 38,and hence first causes the latter to move forwardly relative to thesleeve 40. Accordingly the jaws 22 close and grip the mandrel while thecase 32 is in its foremost position.

As hydraulic pressure in the cylinder 54 builds up, the air pressurebehind the piston 62 is overcome thereby retracting the pulling sleeve40 and jaw case 32 along with the expulsion tube 24 and the adapter 52as the mandrel is tensioned. The grip of the jaws 22 may increase ifthere is slippage of the jaw case 32 with respect to the jaws but theirrelative disposition is maintained by reason of their T-slot connectionto the member 38.

Upon fracture of the mandrel, the valve 73 is automatically reclosed toreverse the flow of hydraulic fluid from the inlet 70 and admit airunder line pressure to the cylinder 56 in front of the piston 76. Sincethe area of the piston 76 subjected to air pressure is considerablygreater than the corresponding area 5 of the face 69 of the member 38,the latter relatively retracts on the pulling sleeve 40 before the airpressure behind the piston 62 can overcome the fluid pressure in frontof it. Consequently the jaws 22 automatically open to release the spentmandrel stem while the jaw case 32 is in its relatively retractedposition. The broken off mandrel portion is thereupon expelledrearwardly through the hose 88 by airflow from the inlet 86. As soon asair pressure rebuilds sufficiently behind the piston 62 the jaws 22 arethereby returned to their open and forward position for receivinganother mandrel rivet.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In a fluid pressure operated head for setting mandrel rivets, a bodyprovided with a mandrel-receiving end for abutting the rivet and fluidpressure mechanism relatively movable axially in the body to tension themandrel for upsetting the rivet when inserted in a workpiece, saidmechanism comprising a jaw case retractable from said body end andhaving a plurality of guideways disposed at a uniform angle about anaxis, mandrel gripping jaws respectively slidable in the guideways, ajaw-controlling member coupled to the jaws to restrain them fromdisplacement relative to one another along the axis, and fluid pressuremeans for retracting the jaw case to cause the jaws to tension themandrel, said fluid pressure means being operable on the jaw-controllingmember to close the jaws in mandrel gripping relation upon relativemovement of the member and the jaw case.

2. A head for setting mandrel rivets, comprising a hollow body having anosepiece for abutting the rivet of a mandrel rivet and receiving itsmandrel stem, said body including in coaxial relative sliding relation atubular jaw holder and a jawcontrolling member, cooperative mandrelgripping jaws within the nosepiece, slidable in the holder, and coupledat their rear ends to the member, piston means respectively operative inspaced cylinder portions of the body and respectively connected to thejaw holder and the jaw-controlling member, and fluid pressure means foractuating the piston means to cause the jaw holder to retract from thenosepiece after closure of the gripping jaws to seize and tension themandrel, and, before the jaw holder is allowed to return, to relativelyreturn the jawcontrolling member to cause the retracted jaws to releasethe mandrel.

3. A rivet setting head as set forth in claim 2 wherein an expulsiontube extends axially in the tubular jaw holder rearwardly from saidjaws, and pneumatic means operatively connected to said tube is adaptedto expel successive spent mandrel stems rearwardly therefrom, saidpneumatic means facilitating retention in the nosepiece of mandrelrivets prior to their being gripped by said jaws.

4. A rivet setting head as set forth in claim 2 wherein the rearwardends of each of said jaws has a T-shaped connection with saidjaw-controlling member whereby their relative axial disposition ismaintained.

1. In a fluid pressure operated head for setting mandrel rivets, a bodyprovided with a mandrel-receiving end for abutting the rivet and fluidpressure mechanism relatively movable axially in the body to tension themandrel for upsetting the rivet when inserted in a workpiece, saidmechanism comprising a jaw case retractable from said body end andhaving a plurality of guideways disposed at a uniform angle about anaxis, mandrel gripping jaws respectively slidable in the guideways, ajawcontrolling member coupled to the jaws to restrain them fromdisplacement relative to one another along the axis, and fluid pressuremeans for retracting the jaw case to cause the jaws to tension themandrel, said fluid pressure means being operable on the jaw-controllingmember to close the jaws in mandrel gripping relation upon relativemovement of the member and the jaw case.
 2. A head for setting mandrelrivets, comprising a hollow body having a nosepiece for abutting therivet of a mandrel rivet and receiving its mandrel stem, said bodyincluding in coaxial relative sliding relation a tubular jaw holder anda jaw-controlling member, cooperative mandrel gripping jaws within thenosepiece, slidable in the holder, and coupled at their rear ends to themember, piston means respectively operative in spaced cylinder portionsof the body and respectively connected to the jaw holder and thejaw-controlling member, and fluid pressure means for actuating thepiston means to cause the jaw holder to retract from the nosepiece afterclosure of the gripping jaws to seize and tension the mandrel, and,before the jaw holder is allowed to return, to relatively return thejaw-controlling member to cause the retracted jaws to release themandrel.
 3. A rivet setting head as set forth in claim 2 wherein anexpulsion tube extends axially in the tubular jaw holder rearwardly fromsaid jaws, and pneumatic means operatively connected to said tube isadapted to expel successive spent mandrel stems rearwardly therefrom,said pneumatic means facilitating retention in the nosepiece of mandrelrivets prior to their being gripped by said jaws.
 4. A rivet settinghead as set forth in claim 2 wherein the rearward ends of each of saidjaws has a T-shaped connection with said jaw-controlling memBer wherebytheir relative axial disposition is maintained.